This invention relates to a mechanism for changing different lenses, and particularly to a mechanism which can provide an optical scanning device with different lenses for different resolution requirements. Different lenses can be switched without additional power. The aforesaid mechanism has a simple structure so as to facilitate the assembling, disassembling and maintenance thereof, and therefore its manufacturing cost will be lowered.
In conventional optical scanning devices, each was designed with a given resolution to meet the user's requirement. A scanner of high resolution is used for input of drawings or words, while a scanner of low resolution is used for input of simple papers. Theoretically, a scanner of high resolution can provide a better scanning quality, but the scanning speed thereof is slower as a result of the increment of scanning spots; therefore, a user may select a faster scanner as long as the resolution requirement is met.
In current conventional scanning devices, the lens thereof is designed for a single resolution; as a restlit, if a user wants to process different papers by means of a scanning input, at least two scanners having different resolutions must be provided, resulting in more money spent; otherwise, the user has to accept poor scanning quality or slow scanning speed. In other words, the lenses of the aforesaid conventional scanning devices would have more or less drawbacks to improve.